HIGH-PERFORMANCE LIQUID-CHROMATOGRAPHIC ASSAY OF BROMOCRIPTINE IN PLASMA AND EYE TISSUE OF THE RABBIT

A reliable reversed-phase high-performance liquid chromatographic meth od has been developed for the determination of bromocriptine (BCT) in plasma and eye tissues. The BCT and propranolol, added as an internal standard (I.S.), were extracted by a liquid-liquid technique followed by an aqueous back-extraction, allowing injection of an aqueous solven t into a 4-mu m Nova-Pak C-18 column (150x3.9 mm I.D.). The mobile pha se was a mixture of 30 parts of acetonitrile and 70 parts of 0.2% trie thylamine (pH 3) at a flow-rate of 1 ml/min. Fluorescence detection wa s at an excitation wavelength of 330 nm and an emission wavelength of 405 nm. The retention times of I.S. and BCT were 4.1 and 11.6 min, res pectively. The calibration curve was linear over the concentration ran ge 0.2-10 mu g/l for plasma (r>0.999) and vitreous humour (r>0.997) an d 1-50 mu g/l for aqueous humour (r>0.985). The limit of quantificatio n was 0.2 mu g/l for plasma and vitreous humour using a 1-ml sample an d was 1 mu g/l for aqueous humour using a 0.2-ml sample. The quality c ontrol samples were reproducible with acceptable accuracy and precisio n. The within-day recovery (n=3) was 100-102% for plasma, 91-106% for aqueous humour and 96-111% for vitreous humour. The between-day recove ry (n=9) was 90-114% for plasma, 83-115% for aqueous humour and 90-105 % for vitreous humour. The within-day precision (n=3) and the between- day precision (n=9) were 1.7-7.0% and 8.1-13.6%, respectively. No inte rferences from endogenous substances were observed. Taken together, th e above simple, sensitive and reproducible high-performance liquid chr omatography assay method was suitable for the determination of BCT in plasma and eye tissues following ocular application of BCT for the the rapy of myopia. (C) 1997 Elsevier Science B.V.